AMeDAS (Automated Meteorological Data Acquisition System), commonly known in Japanese as "アメダス" (amedasu), is a high-resolution surface observation network developed by the Japan Meteorological Agency (JMA) used for gathering regional weather data and verifying forecast performance. The system began operating on November 1, 1974, and currently comprises 1,300 stations throughout Japan (of which over 1,100 are unmanned), with an average separation of 17 km (11 mi).

At unmanned stations, observations are performed every 10 minutes. About 700 of the unmanned stations observe precipitation, air temperature, wind direction and speed, and sunshine duration, while the other stations observe only precipitation.

For about 280 stations (manned or unmanned) located in areas of heavy snowfall, snow depth is also observed.

All the observational data is transmitted to the AMeDAS Center at JMA Headquarters in Tokyo on a real time basis via dedicated telephone lines. The data is then delivered to the whole country after a quality check.